Footing Size Calculator
Isolated footing plan size from column load and safe bearing capacity.
Use SERVICE loads against SBC (it already has FS=2.5–3 inside). 800 kN on 200 kN/m² soil wants a 2.1 m square pad. Depth then comes from punching shear, not bearing.
Formula
Footing Size Calculator is a free footing size for structural engineers, fabricators and site engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Footing Size Calculator
Isolated footing plan size from column load and safe bearing capacity. The calculation implements A = P·(1+10%)/SBC (IS 1080 / IS 456 footing design). Use SERVICE loads against SBC (it already has FS=2.5–3 inside). 800 kN on 200 kN/m² soil wants a 2.1 m square pad. Depth then comes from punching shear, not bearing.
How to use Footing Size Calculator
- 1Enter Column service load in kN.
- 2Enter Safe bearing capacity in kN/m².
- 3Enter Self-weight allowance in %.
- 4Read Required area, Square footing side instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Footing Size Calculator?
- ✓Implements the standard formula — A = P·(1+10%)/SBC
- ✓Reference cited on-page: IS 1080 / IS 456 footing design
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Footing Size Calculator use?+
It computes A = P·(1+10%)/SBC, per IS 1080 / IS 456 footing design. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Use SERVICE loads against SBC (it already has FS=2.5–3 inside). 800 kN on 200 kN/m² soil wants a 2.1 m square pad. Depth then comes from punching shear, not bearing.
Can I use this for real structural design?+
It implements the exact textbook/code formula cited below the result and is ideal for sizing, checking and learning. Final designs should be verified by a qualified engineer against the full code with all load cases.
Is the Footing Size Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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